Questions and Answers From May 24 Mare Reproductive Loss Syndrome Meeting

Following are some of the questions and answers from the informational meeting Thursday about Mare Reproductive Loss Syndrome.

Q: A veterinarian from Minnesota asked if there were
alterations in immune functions in mares during these
syndromes.
A: Dr. Doug Byars: A small number of mares were sick before early fetal loss and late-term abortion, but a majority were not. All recovered successfully. "The immune system is hard to measure, but my gut feeling is they were normal," he said.

Q: Are pastures safe? What about the cherry trees?
A: Dr. Jimmy Henning, a University of Kentucky agronomist, said the pastures are different now than they were in April and early May. Then, he said, the pastures were not growing well and the mares grazed it down to the ground, possibly in close contact with the caterpillars. Since then, there have been several rains, grass growing, and horses are not grazing so close. So, it is safe to turn horses back out into pastures. "I question letting horses graze under cherry trees," said Henning. "I would fence off the cherry trees for an extra measure of safety."

Q: Were the pericarditis and uveitis associated with the mare loss?
A: Dr. Byars said that toxins can affect mycovasculature, and scientists don't always understand the selectivity of the problems associated.

Q: Why aren't other livestock affected?
A: Dr. Lenn Harrison said cyanide is known to causes pericardial fluid to build up in swine. He said he is concerned, but no one is bringing in any samples of other livestock to the Diagnostic Center. "Maybe there is something," he said. "Calving mostly occurs in February and early March, so it's not the right time."

Q: How do you explain early fetal loss in a field with no cherry trees?
A: Dr. Henning said that in every case where there were problems, there were cherry trees in proximity, perhaps in an adjacent field.

Q: Why didn't we see this problem last year when we had a large number of caterpillars?
A: Dr. Henning said that perhaps the dry weather this year had the caterpillars off the tree more.

Q: Should we still use the mycotoxin binder even though no mycotoxins have been found?
A: Dr. Thomas Tobin said that he is not aware of any studies that show mycotoxin binders can bind cyanide.

Q: Is Kentucky hay okay to feed?
A: Dr. Henning said there were zero levels of mycotoxins in all hays tested. However, he said hay buyers should be aware of the potential for caterpillars to be in some hay.

Q: Should we scan sale yearlings' hearts?
Dr. Byars said he has started looking at yearlings, and the general population looks fine. "I haven't found any incidential cases," he said.